Going to Fedora Core 12.4.22-1.2115.nptl fixed the DMA issue. The Seagate SATA drive (ST3160023AS) came up in DMA mode.The speed however (hdparm -t) was 25MB/s, better but still unacceptable.

-2-

I got the latest Fedora Core: 2.4.22-1.2149.nptl

Interestingly enough I found out that this release comes with a sata_sil module that is not even in 2.4.24, it was probably ported from 2.6.1 by the Fedora team.Anyway I believe this is just a RAID driver, it did not change anything (same as -1-).

-3-

Now I decided to live dangerously and I tried tuning max_kb_per_request, the default being 15:

/echo "max_kb_per_request:128" > /proc/ide/hde/settings/

On my first hdparm -t I got 55MB/s !!!

BUT the drive was still making a lot of noise after I got the results, and every time I tried the command again (only waiting a couple seconds before retrying after I got the results), the throughput went lower each time. In 5 retries I was at 7 MB/s. The drive was very noisy, still busy minutes after I was done torturing him.

Unfortunately this did not come as a surprise as I had found the following thread on Google:

> Andre Hedrick wrote:>> />/> />Seagate and Silicon Image are the only two player (well intel now) > who did/> />their own PHY. They did not use the Marvel pairs./> />/> />It is a function of possible ECC on the wire and the relation to the/> />segments in the PIO or SG operations. It is a FIFO issue based on > 512byte/> />boundaries being breached on corner cases./> />/> />The data on the wire is in 8K units./> />/> />It is a 7.5K + 0.5K corner case./> />/> />max_kb_per_request:15 == 7.5K/> />/> />This prevents this corner case until I can code the proper special > case SG/> />table./> />/> />drive->id->hwconfig |= 0x6000;/> />/> />Is needed to fake the driver for device side cable detect./> />There are several issues and I have not had time to keep up./

-3-

The same machine is now dual boot with Windows 2000 SP4. I installed Sandra 2004, a software for benchmnarking, and I got the following results regarding the SATA drive:

I know, comparing results obtained with 2 different benchmarking products is almost irrelevant, but it is enough for the big picture:

There is nothing wrong with the harsware (Seagate or Silicon Image), it works just fine with the windows drivers/libraries ... Oops did I just praise microsoft?

-4-

I compiled/installed a new linux kernel to replace the one from the Fedora distrib with 2.4.24

Absolutely no difference, same as -1-: 25 MB/s

-5-

Now I tried kernel 2.6.1: it is worse, it dropped to 14 MB/s !?!?!I've seem several similar reports about 2.6.

-6-

So at this point I am ready to give up, and to simply buy a PATA drive.

However, after doing all the above (which is reported in chronological order), I booted the latest Fedora Core: 2.4.22-1.2149.nptl again, and decided to give another try to:

echo "max_kb_per_request:128" > /proc/ide/hde/settings

Now I have consistent 55 MB/s and no horrible noise from the drive, and I let this run for 4 hours without any issue. Even typing the "hdparm -Tt" commands one after another results are consistent.

What the heck is going on here (not that I don't appreciate things working, but I'd like to understand)??? I can see only the following possibilities:

- I was lucky, and it all depends on when you change "max_kb_per_request" due to some race condition.- going to 2.6.1, I upgraded 2 packages: quota-tools: went from 3.06 to 3.10 procps: went from 2.0.17 to 3.1.15 I really don't see how this would change anything, but who knows...- running the Win2000 benchmark with Sandra somehow did something to the drive and/or the SATA controller, and they are now friends. Fishy...

Does anybody knows where the default 15kb is coming from for this drive?How can I change this permanently? I mean other than than a hack rc script running at init time...

I understand 2.6.1 is not using /proc/ide/hde/settings, how do I change max_kb_per_request with this kernel?

Anyway I will make several more attempts with max_kb_per_request set to 128, to make sure it is really OK before enforcing it with a script (anyway this script would have to be kernel-version specific, to keep a back door).

Hope I haven't been too long and boring. Comments/suggestions are welcome.

Thanks for your help!

Emmanuel.

Emmanuel Hislen wrote:

>> -----Message d'origine-----> De : Emmanuel Hislen [mailto:hislen@mindspring.com]> Envoye : Saturday, January 24, 2004 1:27 AM> A : Hugo Mills> Cc : linux-kernel@vger.kernel.org> Objet : RE: SiI2112 + Seagate + nFroce2: no DMA!>>>> Hi Hugo,>> I have re-installed my machine with Fedora Core 1 (thinking a newer > version> than RH9 would make the jump to 2.4.24 or 2.6 easier), and this fixed the> DMA issue :-)>> Now my SATA drive is running stable in UDMA6.>> However, performance is still way below expectations.>> I got a huge improvement: my disc read speed (hdparm -t) went from 1.3 > to 25> MB/sec.> This is still slower than my PATA drive on my 3 years old AMD 900 PC > running> Redhat 9.0 (around 35 MB/sec).>> Could you please let me know what you are getting so I know what to > expect?>>> My next step is to try 2.4.24 or 2.6.1 as you suggested, but googling > around> a little bit before I do so I found out a few worrying things:>> - people have reported a drop in performance on SATA in some 2.6 based> kernel (2.6.0-test9), with reported speeds around 20MB/sec. Apparently > there> is no more way to tune max_kb_per_req in 2.6??> - I have found reports that both ide and libdata libraries are limiting> max_kb_per_req to 15 Kb specifically for Seagate drives. So It looks > like I> can't even set it to 128 (I did not even try as I saw reports of memory> corruption).>> So basically since you've got it to work I'd like to know:>> * what speed you get, and what is the RPM of your Seagate> * what is your max_kb_per_req setting (I have 15K)> * what is your accoustic management setting (I have 0)>>> I could not fix the time on linux so I am sending this mail from WinXP > (just> kidding I lost my mails on the linux machine after re-installing :-).>>> Thanks,>>> Emmanuel.>>>> -----Message d'origine-----> De : Hugo Ranger Mills [mailto:hrm@carfax.org.uk]De la part de Hugo> Mills> Envoye : Tuesday, January 20, 2004 12:58 AM> A : manu> Cc : linux-kernel@vger.kernel.org> Objet : Re: SiI2112 + Seagate + nFroce2: no DMA!>>> On Tue, Dec 31, 2002 at 09:55:59PM -0800, manu wrote:>> Incidentally, did you know that the date on your computer is very,> very wrong?>>> I'm about to give up on my SATA drive as I can't get it to work properly.>> So I thought I may try asking the experts before falling back to PATA.>>>> I have seen many mails reporting the same issue, some of them 6-month >> old:>>>> - SATA drive comes up in pio mode, not in dma>> - trying to turn on dma with hdparm is a nightmare: I/O errors, crash>> with data corruption... I tried both:>>>> hddarm -d1 /dev/hde>>>> and:>>>> hdparm -u1 -c3 -d1 -X66 /dev/hde>>>> crash in both cases :-((>>>>>> Here's my equipment:>>>>>> ABIT AN7 motherboard (nForce2 chipset, SiI3112 SATA controller)>> AMD Athlon XP 2600+ (+ 512 DDR / 400 MHz)>> SATA HD Seagate Barracuda 160 Gb>>>> The SATA HD is my only drive. The only thing connected to my IDE>> controllers is a DVD/CD combo.>>>> Running Linux Redhat 9.0>> kernel 2.4.20-28.9>> ^^^^^^^^^^^^^^^^^^> This is your problem. There have been a number of bug-fixes to the> SiI drivers since 2.4.20. Try it again with a newer kernel -- such as> 2.4.24.>>> I've been googling for days now and could not come accross a solution,>> on the contrary I came under the impression that the combination of>> SiI3112 +and Seagate was doomed.>>> Not so. I have a SiI3112 controller and a 120GiB Seagate drive, and> they work very well together. I'm using 2.6.1, although 2.4.23 also> worked well for me.>> [snip]>>> Isn't there a solution??>>>> I am willing to try patches of experimental code. At this point I am>> looking at reinstalling everything on a PATA drive anyway, so I have>> nothing to loose.>>> Try using 2.4.24 or 2.6.1.>> Hugo.>> --> === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===> PGP key: 1C335860 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk> --- All hope abandon, Ye who press Enter here. --->>